Endovascular intervention treatments are performed by implementing a treatment method by which a treatment tool (a device) called a catheter is inserted into a blood vessel so as to treat an affected area in the heart, the brain, the liver, or the like. For example, to perform an endovascular intervention treatment, a medical doctor inserts a catheter with a balloon up to a stenosis site. After that, for example, the medical doctor expands the balloon by injecting liquid into the balloon via the catheter. As a result, the stenosis site is mechanically expanded so that the blood flow is recovered. After the liquid in the balloon is sucked out, the catheter with the balloon is pulled out of the body of the subject by the medical doctor.
Further, an endovascular intervention treatment can also be performed by using a catheter with a balloon that has a metal mesh (called a stent) being in close contact therewith on the outside thereof, for the purpose of preventing recurrence of stenosis in a stenosis site that was once expanded by the balloon. According to this treatment method, a medical doctor expands the stent by expanding the balloon, and subsequently, the liquid in the balloon is sucked out so as to pull the catheter out of the body of the subject. As a result, the expanded stent is left at the stenosis site, and it is therefore possible to reduce the possibility of stenosis recurring at the stenosis site.
To perform endovascular intervention treatments, required to move the device inserted in the blood vessel up to the treated site with an adequate level of precision. Normally, the position of the device is determining by referring to X-ray images that are generated and displayed by an X-ray diagnosis apparatus in a real-time manner. For this reason, in two locations (or in one location), the device has attached thereto metal pieces through which X-rays do not pass, for example, as markers indicating the positions of the balloon or the stent. The medical doctor determines the position of the device by referring to the one or more markers rendered in the X-ray images displayed on a monitor.
However, when an endovascular intervention treatment is performed on a blood vessel in an organ constantly having a pulsating motion such as the heart or in an organ moving due to the pulsating motion, the position of the device in the X-ray images moves constantly. Thus, determining the position of the device while referring to the X-ray images requires an extremely high level of skills of the medical doctor.
To cope with this situation, a technique is conventionally known by which, for example, a moving picture in which the device virtually appears to be stationary is displayed by tracking markers at two points that are rendered in sequentially-generated X-ray images and deforming the images in such a manner that the positions of the markers at the two points in the X-ray images are in the same positions as those in a past image. Further, as a post-processing process, another technique is also known by which the device is displayed in an enhanced manner with high contrast, for example, by calculating an arithmetic mean of images in a plurality of frames that have been corrected to arrange the positions of the markers at two points to be the same among the images.